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step-by-step instructions for building your own GNU/Linux OS
from source code. URL: http://www.linuxfromscratch.org/

One Day One Command
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ltrace — Library call TRACEr

Summary:

ltrace is a program that simply runs the specified command until it
exits and intercepts & records the library/system calls, which are
called by the executed process, and the signals, which are received by
that process. It can used study the internal flow of a program.

Examples:

$ ltrace sleep 1 — Trace all Lib call of ‘sleep’ command.

$ ltrace ls — Trace all Lib call of ‘ls’ command.

$ ltrace -d sleep 1 — Print more detailed info.

$ ltrace -i sleep 1 — Print the value of the Instruction Pointer at

                      every lib call.

$ ltrace -S sleep 1 — Show System Call trace also.

$ ltrace -S -L sleep 1 — Show only System calls.

$ ltrace -r sleep 1 — Print a relative time-stamp with each line of

                      the trace.

$ ltrace -t sleep 1 — Prefix each line of the trace with the time of

                      day.

$ ltrace -o file sleep 1 — Redirect the output to a file.

$ sleep 60 & — Dummy background Job.

$ ltrace -p 1234 — Attach to the process with the PID 1234 (use dummy

                   job’s Pid) and trace.

$ ltrace -n 3 sleep 1 — Indent each new nested call by 3 Spaces.

Read: man ltrace